P.S. Regarding the different hispano marks -- this is slightly off topic, so sue me.
The different hispanos DO have different hits. The fraction of difference is small enough, but notable. The MkV is stronger than the US M2/Hispano2.
Somebody did some hit tests against hangars, seeing how many rounds of every gun it takes to kill them, then dividing by the total rounds fired (something like that). Hispanos II and V had different numbers.
Scroll down to the 3rd post here:
http://www.hitechcreations.com/forums/showthread.php?s=&threadid=171528or copy and paste if that link is too long. It's interesting.
EDIT: I knew I was right, but I got the marks mixed up, the II is just a hair stronger than the V.